TNE30024 Test 2

What does a kernel do?

• hosts the hardware drivers

• hosts the IP and TCP stack

• manages actual communications

what does the Sockets Kernel API do?

• forms the interface that allows the applications layer to make requests on the network

• allows for data transfer to protected kernel layers

what does the socket() function do?

creates a new socket in the OS and returns a handle to it

what does the bind() function do?

attaches a socket to a nominated IP address and port number

what does the listen() function do?

tells the OS to start accepting connections on the TCP socket

what does the accept() function do and what does it do while it waits?

accepts a pending connection on the TCP listening socket

the call blocks until there is a connection pending

what does the connect() function do?

attempts to establish a connection to a remote application

what does the close() function do?

closes the socket to prevent the transmission of data

what does the send() function do, and does it block?

• sends data over the connected socket

• when there is no buffer space left

what does the sendto() function do, and when is it used?

• sends data to a nominated port and IP

• for unconnected UDP sockets

what does the recv() function do, and does it block?

• retrieves data from a connected socket

• if no data is available within the OS

what does the recvfrom() function do, and when is it used?

• receives UDP datagram and provides information on the remote IP and port number

• for unconnected UDP sockets

at which layer is TLS implemented?

the application layer

where does the TLS library sit?

between the application layer and the sockets API

what does the TLS library do?

• validates certificates

• establishes sessions

• selects encryption algorithms and keys

• encrypts data

what are the 2 main purposes of the TLS context?

managing TLS connections

wrapping sockets

that are the 3 steps for making an SSL socket?

1) creating context

2) creating the socket

3) wrapping the socket with the context

what are the 2 parameters of the create_default_context() function?

1) the TLS purpose (server or client)

2) the certificate